A 1000 kg box is being pushed with a force of 3500 N. What acceleration is the

-What can you say about the snowboarder’s kinetic energy as he moves?

Damm [24]

Answer:

His kinetic energy increases, potential energy decreases

The sum of kinetic and potential energy is a constant at any instant before he comes to rest.

Explanation:

Snowboarder is starting from a height and moving to the down direction. As he moves down his velocity increases, we know that kinetic energy is given by the expression $\frac{1}{2} mv^2$ , so as he moves his kinetic energy increases.

When the snowboarder is starting his potential energy is maximum(Potential energy = mgh), as he comes down his potential energy decreases.

Based on this we can conclude that the sum of potential energy and kinetic energy is a constant at any instant for a snowboarder before he comes to rest.

mgh+ $\frac{1}{2} mv^2$ = Constant

7 0

4 years ago

An unknown mass is on a flat frictionless surface and a 2 kg object is attached to it with a string going over pulleyt mounted t

Lynna [10]

Answer:

Explanation:

F=ma

F in this case is the gravity acting on the 2kg object. Acceleration of gravity is 9.8 m/s^2. SF=ma, so

F = 2kg*(9.8 m/s^2) = 19.6 N

Now use this force to determine the mass of the object on the table:

F=ma

19.6 N (1N=kg*m/s^2) = m*(1.8 m/s^2)

m = 10.89 kg

3 0

3 years ago

H20 (water) is an example of a __, as it is made up of two elements.

vova2212 [387]

Answer:

Compound.

Explanation:

A compound is a substance formed when two or more elements are chemically joined. Water, salt, and sugar are examples of compounds. When the elements are joined, the atoms lose their individual properties and have different properties from the elements they are composed of.

8 0

3 years ago

incline plane is given length 12m,load 600 newton,effort 200 Newton, Height 3 metre find its velocity ratio and mechanical advan

Salsk061 [2.6K]

Answer:

i. The velocity ratio of the plane is 4.

ii. The mechanical advantage of the plane is 3.

Explanation:

i. The velocity ratio (VR) of an inclined plane is ratio of its length to the height. It is given as;

VR = $\frac{length of the plane}{height}$ = $\frac{l}{h}$

Given: l = 12 m, L = 600 N, E = 200 N, h = 3 m.

So that,

VR = $\frac{12}{3}$

= 4

The velocity ratio of the plane is 4.

ii. Mechanical advantage (MA) expresses the relationship between the load overcome to effort applied.

MA = $\frac{Load}{Effort}$ = $\frac{L}{E}$

= $\frac{600}{200}$

= 3

The mechanical advantage of the plane is 3.

Therefore, the velocity ratio of the inclined plane is 4, and its mechanical advantage is 3.

7 0

3 years ago

A speeding motorist traveling down a straight highway at 100 km/h passes a parked police car. It takes the police constable 1.0

Lubov Fominskaja [6]

Answer:

t = 7.5 s

Explanation:

The distance traveled by the car at the time of meeting of the two cars must be the same. First, we calculate the distance traveled by the police car. For that we use 2nd equation of motion. Here, we take the time when police car starts to be reference. So,

s₁ = Vi t + (0.5)gt²

where,

s₁ = distance traveled by police car

Vi = Initial Velocity = 0 m/s

t = time taken

Therefore,

s₁ = (0 m/s)(t) + (0.5)(9.8 m/s²)t²

s₁ = 4.9 t²

Now, we calculate the distance traveled by the car. For constant speed and time to be 1 second more than the police car time, due to car starting time, we get:

s₂ = Vt = V(t + 1)

where,

s₂ = distance traveled by car

V = Velocity of car = (100 km/h)(1000 m/1 km)(1 h/ 3600 s) = 27.78 m/s

Therefore,

s₂ = 27.78 t + 27.78

Now, we know that at the time of meeting:

s₁ = s₂

4.9 t² = 27.78 t + 27.78

4.9 t² - 270.78 t - 27.78 = 0

solving the equation and choosing the positive root:

t = 6.5 s

since, we want to know the time from the moment car crossed police car. Therefore, we add 1 second of starting time in this.

t = 6.5 s + 1 s

6 0

4 years ago